Recyclable Monolithic Vitrimer Foam for High-Efficiency Solar-Driven Interfacial Evaporation

With the exponentially rapid development of solar-driven interfacial evaporation, evaporators with both high evaporation efficiency and recyclability are highly desirable to alleviate resource waste and environmental problems but remain challenging. Here, a monolithic evaporator was developed based on a dynamic disulfide vitrimer (a covalently cross-linked polymer network with associative exchangeable covalent bonds). Two types of solar absorbers, carbon nanotubes and oligoanilines, were simultaneously introduced to enhance the optical absorption. A high evaporation efficiency of 89.2% was achieved at 1 sun (1 kW m^-2). When the evaporator was applied to solar desalination, it shows self-cleaning performance with long-term stability. Drinkable water with low ion concentrations satisfying the drinkable water levels of the World Health Organization and a high output (8.66 kg m^-2, 8 h per day) was obtained, revealing great potential for practical seawater desalination. Moreover, a high-performance film material was obtained from the used evaporator via simple hot-pressing, indicating excellent fully closed-loop recyclability of the evaporator. This work provides a promising platform for high-efficiency and recyclable solar-driven interfacial evaporators.